The invention is directed toward the measurement of organic carbon and more particularly concerns the measurement of the amount of organic carbon in aqueous solution. In pollution abatement, medical, and industrial processing situations, for examples, it is often necessary to determine the amount of organic carbon contained in water and aqueous solutions.
The prior art usually requires a combustion step at high temperatures, or requires alternatively, expensive highly purified reactants and/or carrier gases. The resulting carbon products, which may include CO.sub.2, CO or CH.sub.4, are then fed into a measuring device wherein the carbon products are analyzed by such complex measuring systems as infrared spectrophotometry, flame ionization or nephelometry. It will be appreciated that presently available apparatus for the measurement of organic carbon in water are either extremely slow and cumbersome or involve highly sophisticated and expensive equipment.
Soier et al. have described apparatus which uses ultraviolet radiation to oxidize organic carbon into carbon dioxide which is then measured to determine the amount of organic carbon originally in the sample. (Photochemical Method of Determining Organic Carbon, Hydrochemical Materials, Vol. 46, pg. 111, Novocherkassh Hydrochemical Institute, USSR). A sample is funneled into a quartz chamber wherein it is exposed to ultraviolet radiation from a lamp external to the chamber. Organic carbon in the sample is oxidized into carbon dioxide. Purified atmospheric air is pumped through the chamber to transport the generated carbon dioxide to a coulometer which is arranged to measure the quantity of electricity produced by a chemical reaction of the carbon dioxide. Alternatively, volumetric titration may be used for the measurement.
Soier's apparatus exhibits the prior arts disadvantages which limits its utility as a field instrument and capacity for rapid repetitive tests. For example, Soier uses catalyzers maintained at 700.degree.C in the air stream; and further he boils the sample. He does not provide a means to circulate the sample. A condenser using tap water flow is required because of the high temperature. A rather large sample of 30 ml. is used and must be removed from the apparatus before another sample can be introduced by a funnel. Required irradiation time is in the order of three hours unless a sensitizer such as atomic mercury is used.
It would, therefore, be highly desirable for an apparatus to be provided to determine the content of organic carbon in water without the requirement of high temperatures, catalysis, highly purified gases or other materials that may produce an unstable and undesirable background.